Sailboat improvements

ABSTRACT

A fore-and-aft rigged sailboat that has a sail made of flexible material, and includes a flap portion that is adapted to lie on the deck when the sail is in the close-hauled position so as to prevent any substantial flow of air laterally under the sail from the windward to the leeward side thereof. The sail may be either a jib or a mainsail and some embodiments have a transparent panel to provide visibility.

United States Patent 1191 f 1111 3,820,493 Amick June 28, 1974 SAILBOATIMPROVEMENTS 103.

[76] Inventor: James L. Amick, 1464 Cedar Bend Ann Mlgll" 58105" PrimaryExaminer-Trygve M. Blix [22] Filed: Oct. 26, 1972 AssistantExaminer-Stuart M. Goldstein [21] AppL No: 301,231 Attorney, Agent, orFirmOlsen and Stephenson [52] U.S. Cl 114/102, 114/39, 114/103 [51] Int.Cl B63h 9/04 [57] ABSTRACT [58] Field of Search 114/39, 102, 103

A fore-and-aft rigged sailboat that has a sail made of References Citedflexible material, and includes a flap portion that is UNITED STATESPATENTS adapted to lie on the deck when the sail is in the close-2,499,59s 3/1950 Maurer et al. 114/103 hauled Position as anySubstantial flow of 3,438,349 4/l969 Curtis et al. 114/102 air laterallyunder the Sail from the Windward 10 the leeward side thereof. The sailmay be either a jib or a FOREIGN PATENTS OR APPLICATIONS mainsail andsome embodiments have a transparent 83,3l3 l/ 1963 France 114/103 panelto provide visibility OTHER PUBLICATIONS New on Water; Mar. l956;Popular Science, pg. 12 Claims, 4 Drawing Figures PATENTEDJUNZB I974(820,493

SHEET 2 BF 3 I SAILBOAT IMPROVEMENTS BACKGROUND OF THE INVENTION Thepresent invention relates to improvements in sails of the type used infore-and-aft rigged sailboats.

In the use of conventional sails a gap exists between the foot of thesail, often fastened to a boom, and the hull. This gap has a detrimentaleffect in the sailboat performance, because it allows air to flowthrough it from the high pressure or windward side of the sail to thelow pressure or leeward side. It is known from observations on airplanewings that such a flow at a lateral edge of a wing induces a flow in theopposite direction ahead of the wing causing the so-called induced'drag,so that in the case of a sail, the relative wind which the sailexperiences comes from closer to the bow than it would if there were nogap flow. A relative wind closer to the bow produces a sail force whichhas a smaller forward component, and therefore, less propellingcapacity.

The gap between the foot of the sail and the hull is alsodetrimentalfrom the standpoint of the desirability of minimizing theoverturning moment produced by a given sail force.

SUMMARY OF THE- INVENTION The present invention has overcome some of theinadequacies existing in fore-and-aft rigged sailboats, and particularlyin the construction of the sails of such boats.

According to one form of the present invention, a fore-and-aft sail isprovided comprising a sheet of flexible material that. is secured at itsupper end to the mast of the sailboat and extends downward to the deckto form an upright portion and then extends inboard or inward to form aflap portion that is adapted to lie on the deck when the-sail is in theclose-hauled position so as to prevent any substantial flow of airlaterally under the sail from the windward side to the leeward sidethereof. The flexible material preferably includes a transparent panellocated in the upright portion immediately above the flap portion toimprove visibility. This construction and arrangement reduces theinduced rag acting on the sail by preventing air flow from the windwardside of the sail to the leeward side between the sail and the hull. Italso provides an improved ratio of the sail force relative to theoverturning moment by filling the usual gap at the bottom of the sailwith a downward extension of the sail which develops additional sailforce with comparatively little overturning moment.

Thus, it is among the objects of the present invention to provide animproved sail in which induced drag is re duced by elimination of thegap between the bottom of the sail and the hull so as to prevent airflow from the windward side of the-sail to the leeward side between thesail and the hull, the sail-hull juncture being sealed by means of aflap portion which consists of an extension of the sail, part of theflap portion lying in a generbeing had to the accompanying drawingsforming a part of this specification wherein like reference charactersdesignate corresponding parts in the several views.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of afore-and-aft rigged sailboat which includes a mainsail embodying oneform of the present invention;

' FIG. 2 is a fragmentary perspective view of a foreand-aft riggedsailboat which includes a jib embodying another form of the presentinvention;

FIG. 3 is a fragmentary perspective view of a modified form of the jibshown in FIG. 2; and

FIG. 4 is a fragmentary perspective view of a modified form of themainsail shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before explaining the presentinvention in detail, it is to be understood that the invention is notlimited in its application to the details of construction andarrangement of parts illustrated in the accompanying drawings, since theinvention is capable of other embodiments and of being practiced orcarried out in various ways. Also, it is to be understood that thephraseology or terminology employed herein. is for the purpose ofdescription and not of limitation.

Referring now to the drawings, the embodiment of the inventionillustrated in FIG. 1 will be described first. The fore-and-aft riggedsailboat 10 has a deck 12, a mast 14, a swivel 16 mounted on the deck12, and a boom 18 connected at one end to the swivel 16. The mainsail 20is connected at its forward edge to the mast 14, and it has its clew orfirst attachment means 22 connected to the aft end of the boom 18. Themainsail 20 is contoured so as to have an upright portion 24 whichextends from the peak 26 to approximately the level of the clew 22, andan integral flap portion 28 which extends inwardly from the uprightportion 24 so that it can lie on the deck 12 to prevent substantial flowof air laterally under the mainsail 20 from the windward to the leewardside thereof when in the close-hauled position. The flap portion 28 hassecond attachment means 30 in the form of a sleeve extending along theafter edge of the flap portion.

Securing means 32 are provided for positioning the after end of the boom18 and the flap portion 28 in their proper locations. The securing means32 includes the pulley 34 mounted on the end of the boom 18, and atransverse traveller 36 mounted on the hull of the sailboat 10. A line38 is connected at one end to the traveller 36 by a clasp 40 which isadapted to slide on the traveller 36. The other end of the line 38passes through the pulley 34 and from there through a guide tube 42mounted on the boom 18. The line 38 then extends fromthe opposite end ofthe tube 42 to the pulley 44 which is also supported on the boom 18, andthen extends to the jam cleat 46.

Preferably, the mainsail 24 has a window 48 of thin transparent plasticto provide increased visibility which has been reduced from theconventional sails because of the position of the flap portion 28. Theflap portion 28 may be a simple extension of the upper portion of thesail 24, folded over to lie flat on the deck 12. A smoother transitionbetween the curved main part of the sail and the flap portion can beproduced by sewing tucks in the flap, as can be seen in the drawings. Inaddition, the flap 28 may be made of elasticized material to allow forchanges in the sail curvature under varying conditions.

The sleeve 30 through which the line 38 passes is positioned so that itsend nearest the boom is farther from the mast than its other end, whichcomprises the aft inboard corner of the flap portion. Therefore, tensionon the line 38 causes the inboard corner of the flap portion to move asfar inboard as possible. After this comer reaches the traveller 36,further inboard movement of the boom 18 causes the flap portion 28 toarrange itself in fore-and-aft folds.

To move the mainsail 24 from one side of the boat to the other, the line38 is released and the boom and flap portion merely lifted overhead andplaced on the other side. The flap portion 28 will remain on thestarboard side of the boom 18 when the boat is on either a port orstarboard tack, but in either situation the flap portion 28 will beurged by the wind against the deck 12 when in a close-hauled positionsuch as is shown in FIG. 1. The guide tube 42 through which the line 38moves between the two boom pulley 34 and 44 prevents the line 38 frombeing heldinadvertently by the hand that grasps the boom to lift itoverhead.

Attention is now directed to FIG. 2 of the drawings for a more detaileddescription of the invention as applied to a jib. The sail or jib 50includes an upright portion 52 in which is located a window 54 made oftrans parent plastic material which provides improved visibility, and anintegral flap portion 56 extending from the upright portion 52 andcontoured so that it extends inwardly therefrom to lie on the deck 58 ofthe sailboat 60 so as to prevent substantial flow of air laterally underthe sail 50 from the windward to the leeward side thereof, when in theclose-hauled position.

The sailboat 60 includes the mast 62 to which the sail 50 is attached atits upper end. The sail 50 also includes the attachment means or clew 64located at the after edge of the sail adjacent to the lower end of theupright portion 52. The flap portion 56 has an attachment means 66 atits inboard after end and a securing means 68 is provided formaintaining the flap portion in the proper position. In the illustratedform of the invention the securing means includes the cleat 70 and theauxiliary line 72. A line 74 is normally connected to the clew 64 andpasses through the pulley 76 on the deck 58 to the winch 78. Similarcleat 80, pulley 81 and winch 82 are provided on the port side of theboat 60 to be used in conjunction with the sail or jib 50 when thelatter is positioned on the port side of the sailboat. In theconventional manner, a tack 84 is provided for securing to the forwardend or attachment means 86 of the jib or sail 50.

- When the sail 50 is close hauled, essentially all of the flap portion56 is in contact with the deck 58. As the sail is' let out, less andless of the flap portion 56 remains on the deck. The point at which agap begins to show between the aft part of the flap 56 and the hull ofthe boat 60 depends upon how wide the flap portion 56 is made.

From the foregoing descriptions of the two illustrated embodiments, itwill be understood that a sail embody ing the present invention differsfrom the usual sails in that it extends downward to the deck, and whenclose hauled, contacts the deck in such a manner as to substantiallyprevent air flow between the sail bottom and the deck. This isaccomplished by having the lower part of the sail turned inboard as aflap portion which is more or less horizontally disposed on the deck.The pressure difference between windward and leeward sides of the sailtends to seal this flap portion against the deck.

FIG. 3 shows a modified jib 88 which has an upright portion 90 and aflap portion 92, but in this form of the invention a clew 94 is the onlyattachment means provided at the after end of the flap portion 92. Asecuring means 96 comprising the line 98, pulley 100 and winch 102 isprovided for securing the flap portion 92 as well as the remainder ofthe after end of the jib 88 in a desired location.

FIG. 4 shows a modified mainsail 104 which has an upright portion 106and a flap portion 108, and again, this modified sail has only a clewfor securing the after end of the mainsail 104 and its flap portion 108to the boom 112.

In operation, the jib 88 and the mainsail 104 will function essentiallythe same as the corresponding jib 50 and mainsail 20 illustrated inFIGS. 2 and 1, respectively.

It is claimed:

1. In combination, a sailboat that has a mast and a deck, and afore-and-aft sail comprising a sheet of flexible material that issecured at its upper end to said mast and extends downward to said deckand is contoured to form a flap portion of a sufficient dimension to lieon the deck substantially its full fore-and-aft dimension when the sailis in the close-hauled position so as to prevent any substantial flow ofair laterally under said sail from the windward side to the leeward sidethereof, said sail being a jib that has first attachment means at itsforward lower end for fastening a tack, second attachment means at thelower after end of said upright portion for fastening a jib sheet, and athird attachment means at the inboard after end of said flap portion forfastening an auxiliary line.

2. The combination that is defined in claim 1, wherein said flexiblematerial includes a transparent panel located in said upright portionimmediately above said flap portion.

3. A fore-and-aft rigged sailboat having a deck, a mast, a swivel onsaid deck aft of said mast, a boom connected at one end to said swivel,a mainsail connected at its forward edge to said mast and having itsclew connected to the other end of said boom, said mainsail beingcontoured so as to have an upright portion extending from its upper enddownward approximately to the level of said clew and a contiguous flapportion extending inwardly therefrom to a position lower than said boomto lie on said deck to prevent substantial flow of air laterally underthe mainsail from the windward to the leeward side thereof when in theclosehauled position.

4. The fore-and-aft rigged sailboat that is defined in claim 3, whereinsaid flap portion has attachment means at its after end, and securingmeans are fastened to said attachment means for positioning said flapportion.

5. The fore-and-aft rigged sailboat that is defined in claim 3, whereinsaid mainsail has a transparent panel located in said upright portion.

6. A fore-and-aft rigged sailboat having a deck, a mast, a swivel onsaid deck aft of said mast, a boom connected at one end to said swivel,a mainsail connected at its forward edge to said mast and having itsclew connected to the other end of said boom, said mainsail beingcontoured so as to have an upright portion extending from its upper enddownward approximately to the level of said clew and a contiguous flapportion extending inwardly therefrom to lie on said deck to preventsubstantial flow of air laterally under the mainsail from the windwardtothe leeward side thereof when in the close-hauled position, said flapportion having attachment means at its after end, a securing meansfastened to said attachment means for positioning said flap portion,said attachment means comprising a sleeve extending along the after edgeof said flap portion, and said securing means including a line passingthrough said sleeve.

7. The fore-and-aft rigged sailboat that is defined in claim 6, whereinsaid securing means also includes a pulley on the end of said boom, anda transverse traveller mounted on said sailboat, said line beingconnected at one end to said traveller by a clasp adapted to slide onsaid traveller, the other end of said line passing through said pulleyfor controlling the position of the mainsail. 8. The fore-and-aft riggedsailboat that is defined in claim 7, wherein a second pulley is mountedon said boom forward of the first pulley, and a tube extends lengthwiseof said boom, and said line extends from said first pulley through saidtube and said second pulley.

9. A fore-and-aft rigged sailboat having a deck, a mast, a sailconnected at its apex to said mast and having a clew, said sail beingcontoured so as to have an upright portion extending from its upper enddownward approximately to the level of said clew and a flap portionextending inwardly therefrom to lie on said deck to prevent substantialflow of air laterally under the sail from the windward to the leewardside thereof when in the close-hauled position, first securing meansconnected to said clew, said flap portion having attachment means spacedfrom said clew at its inboard after end, and second securing meansconnected to said attachment means for fastening said flap portion withits inward edge on said deck.

10. The fore-and-aft rigged sailboat that is defined in claim 9, whereinsaid first and second securing means comprise lines releasably attachedto said deck.

11. The fore-and-aft rigged sailboat that is defined in claim 9, whereinsaid sail has a transparent panel located in said upright portion.

12. A fore-and-aft rigged sailboat having a deck, a mast, a sailconnected at its apex to said mast and having a clew, said sail beingcontoured so as to have an upright portion extending from its upper enddownward approximately to the level of said clew and a flap portionextending inward therefrom and dimensioned to lie on said deck toprevent substantial flow of air laterally under the sail from thewindward to the leeward side thereof when in the close-hauled position,said flap portion terminating at its after end at said clew, andsecuring means connected to said clew and to said deck holding said clewand said flap portion in close proximity to said deck.

1. In combination, a sailboat that has a mast and a deck, and afore-and-aft sail comprising a sheet of flexible material that issecured at its upper end to said mast and extends downward to said deckand is contoured to form a flap portion of a sufficient dimension to lieon the deck substantially its full fore-and-aft dimension when the sailis in the close-hauled position so as to prevent any substantial flow ofair laterally under said sail from the windward side to the leeward sidethereof, said sail being a jib that has first attachment means at itsforward lower end for fastening a tack, second attachment means at thelower after end of said upright portion for fastening a jib sheet, and athird attachment means at the inboard after end of said flap portion forfastening an auxiliary line.
 2. The combination that is defined in claim1, wherein said flexible material includes a transparent panel locatedin said upright portion immediately above said flap portion.
 3. Afore-and-aft rigged sailboat having a deck, a mast, a swivel on saiddeck aft of said mast, a boom connected at one end to said swivel, amainsail connected at its forward edge to said mast and having its clewconnected to the other end of said boom, said mainsail being contouredso as to have an upright portion extending from its upper end downwardapproximately to the level of said clew and a contiguous flap portionextending inwardly therefrom to a position lower than said boom to lieon said deck to prevent substantial flow of air laterally under themainsail from the windward to the leeward side thereof when in theclose-hauled position.
 4. The fore-and-aft rigged sailboat that isdefined in claim 3, wherein said flap portion has attachment means atits after end, and securing means are fastened to said attachment meansfor positioning said flap portion.
 5. The fore-and-aft rigged sailboatthat is defined in claim 3, wherein said mainsail has a transparentpanel located in said upright portion.
 6. A fore-and-aft rigged sailboathaving a deck, a mast, a swivel on said deck aft of said mast, a boomconnected at one end to said swivel, a mainsail connected at its forwardedge to said mast and having its clew connected to the other end of saidboom, said mainsail being contoured so as to have an upright portionextending from its upper end downward approximately to the level of saidclew and a contiguous flap portion extending inwardly therefrom to lieon said deck to prevent substantial flow of air laterally under themainsail from the windward to the leeward side thereof when in theclose-hauled position, said flap portion having attachment means at itsafter end, a securing means fastened to said attachment means forpositioning said flap portion, said attachment means comprising a sleeveextending along the after edge of said flap portion, and said securingmeans including a line passing through said sleeve.
 7. The fore-and-aftrigged sailboat that is defined in claim 6, wherein said securing meansalso includes a pulley on the end of said boom, and a transversetraveller mounted on said sailboat, said line being connected at one endto said traveller by a clasp adapted to slide on said traveller, theother end of said line passing through said pulley for controlling theposition of the mainsail.
 8. The fore-and-aft rigged sailboat that isdefined in claim 7, wherein a second pulley is mounted on said boomforward of the first pulley, and a tube extends lengthwise of said boom,and said line extends from said first pulley through said tube and saidsecond pulley.
 9. A fore-and-aft rigged sailboat having a deck, a mast,a sail connected at its apex to said mast and having a clew, said sailbeing contoured so as to have an upright portion extending from itsupper end downward approximately to the level of said clew and a flapportion extending inwardly therefrom to lie on said deck to preventsubstantIal flow of air laterally under the sail from the windward tothe leeward side thereof when in the close-hauled position, firstsecuring means connected to said clew, said flap portion havingattachment means spaced from said clew at its inboard after end, andsecond securing means connected to said attachment means for fasteningsaid flap portion with its inward edge on said deck.
 10. Thefore-and-aft rigged sailboat that is defined in claim 9, wherein saidfirst and second securing means comprise lines releasably attached tosaid deck.
 11. The fore-and-aft rigged sailboat that is defined in claim9, wherein said sail has a transparent panel located in said uprightportion.
 12. A fore-and-aft rigged sailboat having a deck, a mast, asail connected at its apex to said mast and having a clew, said sailbeing contoured so as to have an upright portion extending from itsupper end downward approximately to the level of said clew and a flapportion extending inward therefrom and dimensioned to lie on said deckto prevent substantial flow of air laterally under the sail from thewindward to the leeward side thereof when in the close-hauled position,said flap portion terminating at its after end at said clew, andsecuring means connected to said clew and to said deck holding said clewand said flap portion in close proximity to said deck.